'Twinkle Twinkle little star how I wonder what you are? Up above in the world so high like a diamond in the sky’.
As a child we all had a fascination about the world above us. I certainly was always curious about the mysteries of space and what we could find there. When we grew up with movies like ET, there was always this big question ‘Is there life in space?’ This curiosity and eagerness to find answers lead to the birth of the first space exploration initiative. On October 4th 1957, the Soviets launched the first artificial satellite Sputnik 1 and that was the beginning of modern space exploration. Today, space exploration is breaking the traditional mould of Mars being the sole focal point of human attention.
NASA, clearly the world’s biggest space agency is leading a range of space exploration projects. It is on a journey to the ‘Red Plant – Mars’ and aims to send humans to the planet by 2030. When we hear about NASA we instantly think about huge rockets, rovers, orbiters, basically an image appears in our head that shows astronauts flying into space in rockets and then mostly being killed by an alien! This is the imagery we have attained from Hollywood’s obsession with sci-films but the reality of space continues to baffle humanity, both because of its enormity and the numerous possible permutations. Space exploration, though, is more than just finding aliens. It is an attempt at systematically understanding this mysterious universe and analysing the chemical and biological complexities therein. This is the field of astrobiology and it provides an insight into how a combination of biology and chemistry can be used to detect life in space.
Astrobiology is an interdisciplinary scientific field that focuses on the origins, early evolution, distribution, and future of life in the universe. The field investigates the existence of extra-terrestrial life by designing experiments to detect it. Astrobiology makes use of a range of disciplines like molecular biology, biophysics, biochemistry, chemistry, astronomy, physical cosmology, geology etc to investigate the possibility of life in other worlds, and help recognise biospheres that might be different from that on Earth. We are all aware of the ‘Big Bang’ theory and how our universe came to existence, but a question arises that if big bang caused the formation of planet ‘Earth’ which exists in this Goldilocks Zone to foster life, is it theoretically possible that there are other planets or parallel universes also capable of sustaining life? Is it really that rare for life to exist that no other permutation in this vast universe, or possibly multiple other universes, could come up with another way of bringing in new life?
For many years it was perceived that life was solely dependent on energy from the sun – used in different ways by various life forms and inextricably part of the food chain owing to photosynthesis. This was until 1977 when during a deep sea exploration in the Galapagos Rift (located off the coast of Galapagos Islands in the East Pacific Ocean), scientists discovered colonies of giant tube worms, clams, mussels and other creatures clustered around undersea volcanic features known as black smokers. What was astonishing for the scientists was that the depth of the undersea valley prevented sunlight from reaching these creatures. They had thrived for centuries without sunlight, existing as an entirely independent ecosystem. Soon thereafter, scientists discovered bacteria that could produce energy via oxidation of reactive chemicals such hydrogen sulphide – a new autotroph that did not require sunlight, unlike plants. This lead to the discovery of organisms thriving in completely new environments independent of sun’s energy, enduring extreme conditions such as hot temperatures, radioactivity, high pressure, high acidity, toxic conditions etc. The discovery in the Galapagos Rift did not just alter our understanding of life processes, it changed the fundamental question of finding life outside earth. No longer were our assumptions limited by the possibility of finding a place with a habitat similar to that of the earth, or one where previously known creatures could survive. The question of a similar permutation was thrown out of the window, the possibilities expanded endlessly.
The discovery of such organisms lead to a new avenue in astrobiology where characterization of these organisms, their environments, and their evolutionary pathways is considered crucial for understanding how life might evolve elsewhere in the universe. Another interesting organism that has been discovered is a Tardigrade – an invertebrate animal capable of withstanding extreme radiation. Tardigrades accomplish this using some DNA protection proteins in their bodies – something humans and other animals do not have. Such organisms may provide answers as to whether life can survive away from the protection of the Earth’s atmosphere – where radiation was hitherto considered a major threat to existence of life. Scientists are also of the opinion that Jupiter’s moon, Europa, and Saturn’s moon, Enceladus, are the most likely location for extant extraterrestrial life in our solar system. This is due to their subsurface water oceans where radiogenic and tidal heating enables liquid water to exist.
Space is so vast that the quest for finding extra-terrestrial life may always remain a mystery for the remainder of human existence. However, in biological terms, we are not going to find something scary or green that will eat us alive. A lot of answers about what resides above us are already provided by these newly discovered ecosystems on Earth itself. It is just a matter of re-discovering these answers and decoding them on other planets. Astrobiology provides the means for us to explore Earth and space, and form a link between how our universe was created!
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About the Author
Shalini Guleria is currently pursuing her Masters in Tissue Engineering where her research is focused on developing better treatment and detection techniques for Cancer. She is presently associated with Scion Research, New Zealand and holds a Bachelor's Degree in Chemical and Biological Engineering from the University of Waikato, New Zealand. Shalini has won two consecutive national awards at the prestigious Sir Paul Callaghan Eureka Awards for engineers and scientists. Apart from sciences, she is also a highly talented artist.